The present invention relates to fluid brake systems. In particular, the invention is directed to a fluid brake system, including a brake module with an associated accumulator. The accumulator and a method of affixing the accumulator to the brake module are described.
A hydraulic control unit of a vehicle braking system typically includes a number of devices that cooperate to control fluid pressure in a vehicular braking system, and in particular in an anti-lock braking system. Many of the devices, which include solenoids, valves, pumps, attenuators, accumulators and so on, are conventionally housed in a central unit hydraulic body. In a fluid brake system a controlled source of pressurized braking fluid is an essential element. A manually actuated master brake cylinder or an associated hydraulic pump generally provides the pressurized fluid. Accumulators have found use in such systems for providing fluid during brake-apply cycles. Accumulators also provide a point of accumulation for fluid during brake release cycles in systems with antilock functions.
In general, an accumulator includes a device that allows the storage of fluid in a hydraulic system. Prior art accumulators include such devices typically embodied as a spring-loaded piston accumulator positioned within a bore formed in a manifold or housing of a modulator body. In controlling the application of pressure, many systems utilize at least one fluid accumulator that is operative to temporarily receive in-store brake fluid, for example, during pressure reduction phases of the antilock operation. The accumulator typically maintains fluid stored therein at a predetermined pressure maintained by a spring that acts on an accumulator piston. Since, in these systems, the accumulator must be accommodated along with a number of other devices in the interior of the modulator, the size and mass of the modulator body is adversely affected by the inclusion of the integral internal accumulator.
It would be desirable to provide an accumulator for a fluid brake system that reduces the size and mass of an associated modulator body or the like and provide design flexibility. It would be desirable to provide a method of securing an accumulator onto a modulator body that reduces the number of parts and processes therefore. Other benefits of the assembly and method of the present invention will become apparent in the following description and accompanying illustrations.
One aspect of the present invention provides an accumulator assembly for use in a hydraulic control system that includes an accumulator housing including a lower end. The lower end of the housing includes a lead-in portion and a stake groove formed adjacent the tapered lead-in.
Other aspects of the invention provide an accumulator assembly with the tapered lead-in having an angled outer portion angled between about 0 and 15 degrees. The tapered lead-in can have an angled outer portion having an angle between about 5 and 10 degrees. The tapered lead-in can have an angled outer portion having an angle of about 7.5 degrees. The accumulator assembly housing can be made of aluminum. The aluminum can be 2011-T3 aluminum or 6061 aluminum. The stake groove can include a flat annular portion being angled between about 5 and 30 degrees. The flat annular portion of the stake groove can be angled at about 15 degrees. The flat annular portion can be formed adjacent the tapered lead-in and a curved incut portion can be formed adjacent the flat annular portion. The stake groove can be a curved stake groove or a triangular stake groove. The stake groove can include a flange portion. The flange portion can extend outwardly from the accumulator housing. The flange can include an upper surface.
Another aspect of the present invention provides a fluid modulator and accumulator assembly including a fluid modulator having a body including at least one socket formed on an outer surface thereof and an accumulator assembly including a housing including an end portion, the end portion including a tapered lead-in, the tapered lead-in fitted in the socket.
Other aspects of the invention provide a socket with a seizing taper configuration, the angle of the seizing taper being complementary to an angled portion of the tapered lead-in. The end portion of the accumulator housing can include a stake groove formed therein, the stake groove located adjacent the tapered lead-in. The tapered lead-in can include a portion angled between about 5 to 10 degrees. The body can include a stake portion including stake material positioned peripherally with respect to the socket, the stake material can be adapted to deform into the stake groove of the accumulator housing.
Another aspect of the invention provides a method of attaching a modular accumulator to a modulator body including positioning a tapered lead-in of an accumulator housing of the accumulator into a socket formed in an outer portion of the modulator body, applying a force to an outer portion of the accumulator housing, forcing the accumulator housing into a seize position within the socket, and forcing a stake portion of the modulator body into a stake groove formed in the accumulator housing to retain the housing in the socket.
The foregoing and other features and advantages of the invention will become further apparent from the following detailed description of the presently preferred embodiments, read in conjunction with the accompanying drawings. The detailed description and drawings are merely illustrative of the invention rather than limiting, the scope of the invention being defined by the appended claims and equivalents thereof.